Whey is the liquid remaining after the precipitation and separation of casein from milk during cheese elaboration. This whey retains 55% of the nutrients in milk (it is 85-90% of the milk volume) and has high biological and chemical oxygen demand so it is considered a contaminating by-product, and an environmental problem important for dairies.
Until now no technology has been developed that has proven to be sufficiently profitable for processing large volumes of whey. The main drawback is the small number of microorganisms capable of growing in the milk whey. The wild strains of respiring yeasts, such as Kluyveromyces lactis, are unable to achieve alcohol concentrations sufficient to recoup the investment.
The problem posed by the art is to provide a Kluyveromyces lactis strain capable of natively and actively secreting β-galactosidase into the medium capable of achieving alcohol concentrations higher than the wild strain. The solution proposed by the present invention is a Kluyveromyces lactis yeast strain deposited in the Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSMZ) Culture Collection with deposit number DSM 24900, comprising the sequence identified by SEQ ID NO: 1.